Return to Church is multiplayer total conversion of Half-Life 2. Mod is set in around 1999 and takes place in in various church-based settings. Player must choose his destiny either to defend humanity as a slayer or to join vampire family to extend its kin or fight as a member of werewolves clan. Diversity of game is that every team has different classes along with their exclusive weapons, special powers and abilities as well as style of gameplay, like offensive, defensive and stealth.
This video is showing 1st vampire class gameplay.
It's power is polymorphing into bat.
Also you can see feeding on corpse of human.
And the werewolf howl power effect is shown too.
Everything is on rtc_trade map.
YouTube version with annotations.